One ubiquitous form of window treatment is the roller shade. A common window covering during the 19th century, a roller shade is simply a rectangular panel of fabric, or other material, that is attached to a cylindrical, rotating tube. The shade tube is mounted near the header of the window such that the shade rolls up upon itself as the shade tube rotates in one direction, and rolls down to cover the a desired portion of the window when the shade tube is rotated in the opposite direction.
A control system, mounted at one end of the shade tube, can secure the shade at one or more positions along the extent of its travel, regardless of the direction of rotation of the shade tube. Simple mechanical control systems include ratchet-and-pawl mechanisms, friction brakes, clutches, etc. To roll the shade up and down, and to position the shade at intermediate locations along its extend of travel, ratchet-and-pawl and friction brake mechanisms require the lower edge of the shade to be manipulated by the user, while clutch mechanisms include a control chain that is manipulated by the user.
Not surprisingly, motorization of the roller shade was accomplished, quite simply, by replacing the simple, mechanical control system with an electric motor that is directly coupled to the shade tube. The motor may be located inside or outside the shade tube, is fixed to the roller shade support and is connected to a simple switch, or, in more sophisticated applications, to a radio frequency (RF) or infrared (IR) transceiver, that controls the activation of the motor and the rotation of the shade tube.
Many known motorized roller shades provide power, such as 120 VAC, 220/230 VAC 50/60 Hz, etc., to the motor and control electronics from the facility in which the motorized roller shade is installed. Recently-developed battery-powered roller shades provide installation flexibility by removing the requirement to connect the motor and control electronics to facility power. The batteries for these roller shades are typically mounted within, above, or adjacent to the shade mounting bracket, headrail or fascia. Unfortunately, these battery-powered systems suffer from many drawbacks, including, for example, high levels of self-generated noise, inadequate battery life, inadequate or nonexistent counterbalancing capability, inadequate or nonexistent manual operation capability, inconvenient installation requirements, and the like.
Therefore, to improve the battery life of battery-powered roller shades and, thus the expenses associated with operation of the battery-powered roller shades, a new, low-power roller shade is needed.
Another problem in the industry is that many motorized window shades do not allow for manual movement. That is, when the motorization components are added to a window shade the window shade can no longer be moved by hand. As one example, a certain hotel in Las Vegas, Nev. installed a great number of motorized shades in their rooms. While the functionality of motorized shades was an added advantage, an unforeseen problem arose when patrons of the hotel, who were unaware that the shades were movable only by way of motorization, attempted to open or close the shades manually. This manual movement would break the internal gears of the shades requiring replacement at great inconvenience and cost. This breakage is a result of the arrangement where the motor is designed to rotate fast requiring a substantial gear reduction. This substantial gear reduction causes a great amount of back drive in the motor when someone tugs on it in an attempt to make it manually move which causes the gears to break.
Therefore, to improve upon these prior art motorized window shades, an improved shade is needed that allows for manual movement as well as motorized movement.